package com.yellowcong.filter;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.shiro.authc.AuthenticationException;
import org.apache.shiro.authc.AuthenticationToken;
import org.apache.shiro.web.filter.authc.BasicHttpAuthenticationFilter;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.RequestMethod;

import com.yellowcong.token.JwtToken;

public class JwtFilter extends BasicHttpAuthenticationFilter {

	/**
     * 对跨域提供支持
     */
    @Override
    protected boolean preHandle(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        httpServletResponse.setHeader("Access-control-Allow-Origin", httpServletRequest.getHeader("Origin"));
        httpServletResponse.setHeader("Access-Control-Allow-Methods", "GET,POST,OPTIONS,PUT,DELETE");
        httpServletResponse.setHeader("Access-Control-Allow-Headers", httpServletRequest.getHeader("Access-Control-Request-Headers"));
        // 跨域时会首先发送一个option请求，这里我们给option请求直接返回正常状态
        if (httpServletRequest.getMethod().equals(RequestMethod.OPTIONS.name())) {
            httpServletResponse.setStatus(HttpStatus.OK.value());
            return false;
        }
        return super.preHandle(request, response);
    }


	/**
     * 判断用户是否想要登入。
     * 检测header里面是否包含Authorization字段即可
     */
    @Override
    protected boolean isLoginAttempt(ServletRequest request, ServletResponse response) {
        HttpServletRequest req = (HttpServletRequest) request;
        String authorization = req.getHeader("Authorization");
        return authorization != null;
    }

	@Override
	protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) {
		try {
			executeLogin(request, response);
			return true;
		} catch (Exception e) {

			this.responseUnAuth(request, response);
			return false;
		}
	}
	/**
     * 将非法请求跳转到 /401
     */
    private void responseUnAuth(ServletRequest req, ServletResponse resp) {
        try {
            HttpServletResponse httpServletResponse = (HttpServletResponse) resp;
            httpServletResponse.sendRedirect("/user/unauthorized");
        } catch (Exception e) {
        }
    }


	/**
	 * 过滤器，每次登陆的时候，都从Header的Authorization 字段中，获取到token,然后执行登陆的操作
	 */
	@Override
    protected boolean executeLogin(ServletRequest request, 
                                   ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        //header 需要这个字段
        String token = httpServletRequest.getHeader("Authorization");
        JwtToken jwtToken = new JwtToken(token);
        
        String url = ((HttpServletRequest)request).getRequestURI();
        System.out.println(url);
        
        // 提交给realm进行登入，如果错误他会抛出异常并被捕获
        getSubject(request, response).login(jwtToken);
        // 如果没有抛出异常则代表登入成功，返回true
        return true;
    }
	
	

}
